FWIW If you have Super Street Fighter 4, it's been out as DLC for awhile.

It's a nice change of pace from SSF4 i suppose. I think people are going to miss the really good character balance of SSF4 since that has largely gone out the window.

How so?

The dominance of Fei Long, Yun, and Yang as well as the nerfs to a fair amount of previously good characters creates a definite gap between the top 3 and the rest of the cast. A lot of people feel like if you want to be competitive, you have to play them (One of the current jokes is AE should be renamed to Street Fighter 4: Hong Kong Edition). It's pretty safe to say everyone is learning one of those 3 characters for Evo.

I personally am not calling Yun or Yang overpowered, but they're very clearly better than the rest of the cast with their only "bad" match-up being Zangief.

Yep. He was very good in Super and his buffs outweigh his nerfs so he only got better.

I guess I should throw C.Viper in there as well because she hardly had any changes. Her biggest buff is that overall damage got lowered across the board which increased her survivability because she has low stamina to begin with. Another factor is that a lot of previously good characters in SSF4 got nerfed anywhere from a little bit to a lot (worst case Honda, who was one of her worst match-ups) which obviously makes her a better by comparison as she has less bad match-ups. However in the grand scheme of things, her getting better doesn't change much since no one plays her much due to viper being very difficult to play effectively execution wise.

So, how many times do they plan on reselling the same game? I still don't see "Turbo" in the title, so I'm guessing at least one more time.

Well, it's kind of up in the air. After they released Arcade Edition, Yoshinori Ono stated a couple times, on record, that Arcade Edition was the last entry of the Street Fighter 4 series and Street Fighter X Tekken was the next step. Since AE has been released on console, there has been a lot of requests (or so they say) for continued re-balancing as well as new characters. Capcom said maybe and that they would think about it. That's pretty much the current state of things.

It's a bit easier to swallow now that you can just download it instead of paying $40 for the new version.

Fair enough I suppose, are these versions actually compatible with each other or are you forced to keep buying these updates if you want to stay in the competitive scene?

They are sort of compatible. If you have Arcade Edition, you can go back to "Super SF4" with a click of the button and play against people who only have SSF4. Yun, Yang, Oni, and Evil Ryu are not available to be used and the balance changes will revert back to Super SF4. People who only have Super SF4 will only be able to play against other people who have Super SF4 and people with Arcade Edition who are in "Super SF4" mode (which is hardly anybody).